Vacuum controlled unloading valve



Aug. 7, 1934. o. E. BLACK 1,963,985'

VACUUM CONTROLLED UNLOADING VALVE Filed Oct. 27, 1935 Patented Aug. 7, 1934` 1,968,985

:.UNITED STATES PATENT OFFICE 'VACUUM coNrRoLLED UNLOADING vaLvE Otto E. Black, Dayton, Ohio, assignor to The Dayton Air Compressor Company, Dayton, Ohio, a corporation of Ohio Application october 27, 1933, serial No. 695,477

sciaims. (onse-24) Thisvinvention vrelates to new and useful imber through a pressure line 16 including a provements in `vacuum-controlled unloading check valve 17, to the storage tank 3. The inlet valves 'for iiuid compressors and the like. port 18 of the low pressure head 6 has connected It is one of the principal objects of my inthereto a short nipple 19 to whose lower thread- 5 vention to' provide a vacuum-controlled unloaded end of a T tting 20 is secured. The end so ing valve which is actuated from the inlet side of the T opposite the nipple 18, has therein of a compressor in such a manner that it will an internally threaded opening 21 in which is operate unfailingly, regardless of the tank or adjustably positioned the upper threaded end outlet pressure, or of line current failure that of a sleeve valve 22. (See Figures 1 and 2.) l0 produces a premature `stopping of the comlThe sleeve valve 22 has in the wall of its 65 presser when `motor-operated. threaded end a series of circumferentially It is still another object of my invention to spaced, open slots 23, through which iiuid is provide an unloading valve of rugged construcadmitted to the inlet port 18. The opposite end tion `that will not be ail'ected by dust particles of the valve 22 is effectively closed by a hexal inthe air lines. Eon cap 24 by which the valve 22 may be 70 My vacuum controlled unloading valve when screwed into or out of the threaded opening`2l given its initial adjustment at the timeof manofthe T 22 to decrease or increase the length ufacture,'will not require further or frequent adof the openings or slots 23, thus regulating the `Mjusti'nent inthe iield. Y amount of fluid admitted.

By its positive and unfailing action in 'in- Between the threaded end of the sleeve22 and 75 stantly relieving the entrapped pressure within the cap 24, the top convex cover 25 of a muliler the cylinder of a fluid compressor, my unload- 26 is rmly held between lock nuts 27-27 on ingvalve also prolongs the life of the source of the threaded portion of the sleeve. When the motive'power by preventing the burning out of sleeve valve 22 is in its finally adjusted posithe motor and slipping belts due to heavy loads tion, the muffler 26 israised by the lock nuts 27, 50 vwhen starting. 27 to a position abutting the lower end of the other important and incidental objects of T ntting 20 to bring the lower ends of the slots my invention will be brought out in the iollow- 23 within the muilier, asillustrated in Figure 4Q ing specification and the claims annexed there- Depending from the crimped edge 28 of the to, i cover 25 are the side walls 29 and perforated 85 In the accompanying drawing illustrating one convex bottom 30 or the muier 26, the latter embodiment` of myinvention, Figure 1 is a side being readily detachable from the cover to eiect view of a two stage, opposed, iluid compressor adjustment of the sleeve valve 22. (See Figequipped with my vacuum-controlled unloading 'ures 1 and 2). valve. Figure 2 is a sectional view through my Communicating with a lateral opening 31 ot 9o vacuum-controlled unloading valve mechanism, the T 20 through a short nipple 32, is a. diand Figure 3 is an enlarged view of the valve aphragm housing 33 having oppositelydisposed f, employed with the diaphragm control. convex heads 34and 35 between whose adjacent Referring `now to the drawing fora complete anges 36 and 37 a flexible diaphragm 38 is disclosure of my invention. in Figure 1 I have securely held by flange bolts 39. Positioned 95 shown a two-stage opposed fluid compressor 1 between the diaphragm 38 and the head 35 is mounted on a sub-base 2 and supported upon a a. conical compression spring 40 whose one end storage tank 3. bears against the inner face of the head On oppositely disposed sides of a crank case and whose opposite end is received by a flanged 4 is a low pressure cylinder 5 having a cylinder pressure diSC 41 that distributes the Spring pres- 100 head 6, and a high pressure cylinder 7 prosure uniformly over the surface of the diaphragm vided with a cylinder head 8. Attached to against which it is forced. (See Figure 2.) the outlet port 9 oi the head 6 is a discharge Formed in the center ofthe head 34, opposite line 10 connected with a lateral cylinder head the nipple 32, is a threaded boss 42 which sup- Y connector 11, and extending through an inlet ports an unloading valve 43. As shown in Fig- 105 line 12 to the inlet port 13 of the head 8. (See ure 3, the valve 43 has a T shaped body 44 pro- Figure 1.) vided with a passage and intercepting near the The discharge port 14 of the head 8 is concenter of the body a lateral passage 46. Adnected with a vertical cylindrical air chamber jacent the boss 42, the passage 45 is enlarged to 15. The compressed fluid ows from the chamreceive slidably therein, an actuating pin 47 to 110 

